Phenylethanoid glycosides from the stems of Callicarpa peii (hemostatic drug)

Abstract

Two new trisaccharide intermediates of phenylethanoid glycosides, peiioside A(1)/A(2) (1a/1b) and peiioside B (2), were isolated from the n-BuOH fraction of MeOH extract of the stems of Callicarpa peii H.T. Chang, together with five biogenetic relevant known compounds 3-7. The structures of compounds 1 and 2 were elucidated by extensive spectroscopic methods (especially 2D-NMR techniques) and acid-catalyzed hydrolysis as O-α-l-rhamnopyranosyl-(1″→3')-O-[β-d-apiofuranosyl-(1‴→6')] -4'-O-[(E)-caffeoyl]-d-glucopyranoside] (1a/1b), 3,4-dihydroxy-β-phenylethoxy-O-[β-d-apiofuranosyl-(1‴→6')-α-l-rhamnopyranosyl-(1″→3')-O-β-d-glucopyranoside] (2), respectively. On the basis of the isolated compounds, a presumable biogenetic pathway of the biologically interesting phenylethanoid glycosides about forsythoside B (3) and acteoside (4) isolated from this species was proposed. Isolation of five related intermediates (1-2, 5-7) provided further support for the biogenetic path. This is the first report about phytochemical research on C. peii and the biogenetic hypothesis of forsythoside B and acteoside.